Endovascular cerebrospinal fluid shunt

ABSTRACT

Implantable shunt devices and methods for draining cerebrospinal fluid from a patient&#39;s subarachnoid space include a shunt having opposed first and second ends, the second end being constructed to penetrate a wall of a sigmoid, transverse, straight, or sagittal sinus of the patient, a one-way valve, a hollow passageway extending between the second end and the one-way valve such that cerebrospinal fluid can be drained through the second end and out through the valve, and a mechanism coupled to the shunt and configured to anchor the shunt at a desired location proximal to the subarachnoid space.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/480,543 filed on Apr. 6, 2017, which is a continuation of U.S.application Ser. No. 14/596,335 filed on Jan. 14, 2015, which is acontinuation of U.S. application Ser. No. 14/259,614 filed on Apr. 23,2014, which claims priority to U.S. Provisional Application No.61/927,558 filed on Jan. 15, 2014, the contents of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to shunts capable of drainingcerebrospinal fluid to the venous system.

BACKGROUND

It is known to treat hydrocephalus by draining cerebrospinal fluid (CSF)from the brain with a drain tube, catheter or shunt. See U.S. Pat. Nos.5,385,541 and 4,950,232. These known devices are complex and invasive.The risk for infection is also increased due to the complexity of thesedevices.

The known shunts are limited to areas of placement due to fluid flowcontrol; however, fluid flow still poses difficulties due to thecomplexity of the devices and the placement areas. Commonly, theshunts/catheters are placed through the skull of the patient. Thisplacement requires an open surgical procedure performed under generalanesthesia. The shunts/catheters also require pressure control tofacilitate CSF flow. Moreover, the known shunts and methods ofplacements do not work in conjunction with a body's natural diseasecontrol processes.

Thus, there is a need for an endovascular shunt that can be insertedinto the venous system percutaneously, without the need for open surgeryand concomitant risk of infection.

SUMMARY

The present disclosure relates to endovascular CSF shunts that drain CSFfrom the subarachnoid space around the cerebellum into a dural venoussinus. As used in the present disclosure, the phrase “dural venoussinus” and other references to the term “sinus” mean the sigmoid sinus,transverse sinus, straight sinus, or sagittal sinus.

The present disclosure also relates to methods of draining CSF byinserting, and deploying, and optionally detaching, one or more of theshunts disclosed herein by an endovascular route through the venoussystem. For example, the venous system may be accessed either throughthe femoral vein or the jugular vein percutaneously.

The endovascular cerebrospinal fluid shunt devices as described hereinare an improvement over the standard cerebrospinal fluid shunts, becausethey can be placed into a patient percutaneously via a catheter insertedinto the venous system of the body through a needle hole, without theneed for open surgery and the skin incisions required with current shuntdevices. In some patients, the shunt devices can be inserted withoutgeneral anesthesia, which is not possible with current cerebrospinalfluid shunts. The shunt devices also will allow for more physiologicdrainage of cerebrospinal fluid since the device is shuntingcerebrospinal fluid into the same cerebral venous system that occursnaturally in people without impaired CSF drainage.

One aspect of the present disclosure is to provide implantable shuntdevices for draining fluid from a patient's subarachnoid space. Thedevices include a shunt having opposed first and second ends. Thedevices also include a one-way valve and a tip configured to penetratethe sinus “wall” (e.g., a wall of dura) to access the subarachnoidspace. In some embodiments, a one-way valve is located at the first endof the shunt and a helical tip is disposed at the second end. In use,the helical tip penetrates the sigmoid sinus wall of the patient and ahollow passageway extending between the helical tip and the first endallows the CSF to be drained through the helical tip and out through thevalve.

Another aspect of the present disclosure provides methods for drainingcerebrospinal fluid from a patient's subarachnoid space. The methodsinclude providing a shunt having opposed first and second ends,delivering the shunt to the sinus wall, implanting the helical tip inthe sinus wall of the patient; and draining cerebrospinal fluid from thepatient.

In another general aspect, implantable shunt devices for drainingcerebrospinal fluid from a patient's subarachnoid space include a shunthaving opposed first and second ends, the second end being constructedto penetrate a wall of a sinus of the patient, a one-way valve disposedat either end or between the ends of the shunt, a hollow passagewayextending the length of the shunt such that cerebrospinal fluid can bedrained through the second end, valve, and first end into the sinuslumen. The shunt device can also include a mechanism coupled to theshunt and configured to anchor the shunt at a desired location proximalto the subarachnoid space.

Aspects may include one or more of the following features in variouscombinations as indicated in the appended claims.

The shunt device may be sized and configured to be positioned within thesigmoid sinus, transverse sinus, straight sinus, or sagittal sinus. Theshunt device can include a stent device configured for insertion intothe sinus of the patient. The stent device can include a helical coil.The helical coil can be self-expanding. The stent device can include aself-expanding basket. The stent device can include a circumferentialmesh. The circumferential mesh can be self-expanding. The stent devicecan include a plurality of individual coils coupled to a connectingmember. Each coil of the plurality of coils can be self-expanding.

The shunt device can include a helical tip configured to be positionedwithin the subarachnoid space. The shunt device can include a coiledcannula with a three-dimensional shape, wherein the coiled cannula isconfigured to be positioned within the subarachnoid space. The coiledcannula can be configured to realize its three-dimensional shape uponbeing positioned within the subarachnoid space. The shunt device caninclude an umbrella shaped screen configured to be positioned within thesubarachnoid space. The umbrella shaped screen can be configured torealize its umbrella shape upon being positioned within the subarachnoidspace. The shunt device can include a globe shaped screen configured tobe positioned within the subarachnoid space. The globe shaped screen canbe configured to realize its globe shape upon being positioned withinthe subarachnoid space.

Aspects may include one or more of the following advantages.

Among other advantages, the portions of the endovascular cerebrospinalfluid shunt (eCSFS) devices that are specifically designed be placedinto the cerebral spinal fluid (CSF) space (e.g., the subarachnoidspace) can be shielded from the surrounding brain parenchyma (e.g., thecerebellum) by a shielding mechanism, e.g., a stent-like orumbrella-type device, advantageously enabling the continuous flow ofcerebral spinal fluid through the device. That is, certain embodimentsdescribed herein include shielding mechanisms that reduce or mitigatethe potential occlusion of openings in eCSFS devices that are designedto enable the passage of CSF through the device by structurallyseparating, e.g., pushing back, the brain parenchyma from thesubarachnoid portions of the eCSFS device. Additionally, these shieldingmechanisms can also create and maintain a space for CSF to pool withinthe subarachnoid space. Maintaining a well-defined space for CSF to poolaround the subarachnoid portion of the eCSFS device ensures that CSFwill flow to the venous system and enables the shunt device tooperatively maintain normal intracranial pressure by draining excess CSFfrom the subarachnoid space.

The use of stents in conjunction with or as a part of the shunt devicesdescribed herein results in a better anchoring of eCSFS devices in theirdesired locations. The use of stents can also simplify the process ofdelivering and implanting eCSFS devices.

Use of a radiopaque material to form a ring or other marker for a stentmounted port provides the advantage that the stent mounted port can beeasily located using fluoroscopy techniques.

Use of a specialized catheterization apparatus including two or morestabilization balloons permits passage of blood around the balloon andthrough the sigmoid sinus, transverse sinus, straight sinus, or sagittalsinus during implantation of an eCSFS device. Since blood is permittedto flow around the stabilization balloons, venous drainage of thecerebral tissue continues during implantation of the eCSFS device.

These and other features, aspects, and advantages of the presentdisclosure will become more apparent from the following detaileddescription relative to the accompanied drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an anatomy of the venous system in the skull ofa human.

FIG. 2 is a schematic of a top view of a human skull base with the brainremoved illustrating the placement of an endovascular shunt penetratingthe sigmoid sinus wall into the subarachnoid space.

FIG. 3 is a partial cross-section of an embodiment of the endovascularshunt of FIG. 2.

FIG. 4 illustrates the delivery of the endovascular shunt of FIG. 3 tothe CSF space of a patient's venous system.

FIG. 5 illustrates the implantation of the endovascular shunt of FIG. 3into the sigmoid sinus wall.

FIG. 6 illustrates the endovascular shunt of FIG. 3 implanted in thesigmoid sinus wall.

FIG. 7 shows a self-expanding coil type stent disposed within a sigmoidsinus.

FIG. 8 shows an alternative embodiment of a self-expanding stentdisposed within a sigmoid sinus.

FIG. 9 shows yet another alternative embodiment of a self-expandingstent disposed within a sigmoid sinus.

FIG. 10 shows a self-expanding coil type stent disposed within a sigmoidsinus.

FIG. 11 shows a stent-mounted port disposed within a sigmoid sinus.

FIG. 12 shows a stent-mounted port disposed within a sigmoid sinus andhaving an endovascular cerebrospinal fluid shunt device insertedtherein.

FIG. 13 shows a corkscrew type self-anchoring endovascular cerebrospinalfluid shunt device.

FIG. 14 shows three-dimensional coil type self-anchoring endovascularcerebrospinal fluid shunt device.

FIG. 15 shows an umbrella type self-anchoring endovascular cerebrospinalfluid shunt.

FIG. 16 shows a first globe type self-anchoring endovascularcerebrospinal fluid shunt device.

FIG. 17 shows a second globe type self-anchoring endovascularcerebrospinal fluid shunt device.

FIG. 18 shows a schematic of a catheterization apparatus inserted withina patient's sigmoid sinus with its stabilization balloons inflated.

FIG. 19 shows a cross-sectional view of the catheterization apparatus ofFIG. 18.

FIG. 20 shows a schematic of an endovascular cerebrospinal fluid shuntbeing implanted through the catheterization apparatus.

FIG. 21 shows the catheterization apparatus after shunt implantationwith deflation of the balloon and expansion of the globe in thesubarachnoid space.

FIG. 22 shows the catheterization apparatus being withdrawn from thepatient's sigmoid sinus.

FIG. 23 shows a catheterization apparatus for patency testing.

DETAILED DESCRIPTION

1 Endovascular Shunt Device

Referring to FIG. 1, a first view of a patient's head illustrates thatthe endovascular shunt devices and stents described herein can bedelivered to a preferred location 102 of placement in the medial wall ofthe sigmoid sinus 104 of the venous system 110 of a patient 108.Alternatively, the shunt devices and stents described herein can bedelivered to the other large diameter dural venous sinuses disclosedherein: the transverse sinus, straight sinus, or sagittal sinus shown inFIG. 1.

Referring to FIG. 2, a second view of the patients head illustrates thatin general, the endovascular shunt devices can be delivered to the rightor left sigmoid sinus 12A, 12B of a patient's skull 10 via either theright or left jugular vein, respectively, of the venous system. Thesigmoid sinus lumen 12 is located between the temporal bone (FIGS. 4-6)and the cerebellum.

A shunt 20 is implanted into a sigmoid sinus wall 16, so that one endcommunicates with CSF located in the cistern or CSF space 18 around thecerebellum 19. The device of the present disclosure uses the body'snatural disease control mechanisms by delivering the CSF from cistern 18into sigmoid sinus lumen 12 of the venous system. The venous system ofthe patient can be accessed either through the femoral or jugular veins(not shown) percutaneously. It should be appreciated that the shuntdevice of the present disclosure can be delivered to the sigmoid sinusvia other veins.

As shown in FIG. 3, one embodiment of the endovascular CSF shunt 20 ofthe present disclosure includes opposed first and second ends 22, 24. Aone-way valve 26 is located at first end 22. As will be describedfurther herein, CSF can travel through shunt 20 and out end 22, however,other fluid (e.g., blood) cannot enter the shunt from open end 22.

A helical tip 30 is located at second end 24. As will be describedfurther herein, helical tip 30 has a closed sharpened end 31 that isadapted to penetrate sinus wall 16. Tip 30 includes a plurality ofapertures 34 through which the CSF enters the tip. A hollow passageway32 extends from tip 30 and open end 22, such that the CSF fluid enteringthrough apertures 34 can pass through valve 26 and pass from an outlet36.

Referring to FIGS. 4-6 and as described above, a delivery catheter 40 isdelivered to the venous system proximate the brain via the femoral orjugular vein. Catheter 40 is inserted into sigmoid sinus lumen 12 at aproximal location 13 toward the neck and inserted toward a distal end15, which is toward the brain.

Delivery catheter 40 includes a second lumen 44 and a shunt deliveryport 42. Lumen 44 directs the entire catheter to the correct locationwith for example, a guide wire, to allow injection of intravenouscontrast to visualize the venous lumen. Lumen 44 also supports balloons46 that can be deployed to temporarily occlude venous flow during stuntimplantation. Shunt 20 is positioned at an end of an internal catheter48 that is manipulated through catheter 40 and port 42. To preventthrombosis within the sigmoid sinus and around the endovascular shunt,shunt 20 can be provided with an anti-thrombic coating.

As shown in FIG. 5, internal catheter 48 facilitates twisting of shunt20 so that it penetrates through sigmoid sinus wall 12. Catheter 48includes a hollow lumen to allow CSF withdrawal after shunt penetrationof the sigmoid sinus wall to confirm that CSF is flowing through theshunt. However, catheter 48 must be rigid enough to allow twisting ofthe shunt such that it penetrates the sigmoid sinus wall. Uponinsertion, helical tip 30 extends into cistern 18 and CSF locatedtherein. A projection 28 located on shunt 20 between the ends abuts thewall and prevents the shunt from passing therethrough. Upon placement,internal catheter 48 is detached. The CSF can also be aspirated backprior to detachment of catheter 48.

Thereafter, delivery catheter 40 can be removed and shunt 20 isimplanted as shown in FIG. 6. CSF 50 draining from outlet 36 from CSFspace 18 is delivered to the venous blood flow 17 where it mixes withthe blood and passes through the blood stream It also should beappreciated that shunt 20 can incorporate different tips at its end anddifferent mechanisms for penetrating the dura.

Thus, the endovascular CSF shunt devices described herein can be placedinto a patient percutaneously via a catheter inserted into the venoussystem of the body through a needle hole, without the need for opensurgery, creating a burr hole in the skull, or passing a catheterthrough cerebellum to access a CSF-filled ventricle. In some patients,the device can be inserted without general anesthesia, which is notpossible with current cerebrospinal fluid shunts. The device also willallow for more physiologic drainage of cerebrospinal fluid since thedevice is shunting cerebrospinal fluid into the same cerebral venoussystem that occurs naturally in normal people.

2 Shunt Stabilization

Specialized stabilization devices and delivery guide catheters have alsobeen developed to facilitate implantation and stabilization ofendovascular cerebral spinal fluid shunt (eCSFS) devices within thesigmoid sinus, transverse sinus, straight sinus, or sagittal sinus of apatient.

2.1 eCSFS Device Stabilization Devices

In certain situations, an eCSFS device which is implanted in a wall ofthe sigmoid sinus of a patient or other sinus described herein canmigrate (e.g., dislodge) from the wall, degrading the ability of theeCSFS device to drain cerebral spinal fluid from the patient'ssubarachnoid space. In some examples, to address this problem, astent-like device is used to anchor the eCSFS device into the wall ofthe aforementioned sinus and to provide a platform to prevent migrationof the eCSFS device after deployment.

2.1.1 Self-Expanding Coil Type Stents

Referring to FIG. 7, one example of a stent 700 is implemented as aself-expanding coil, which is coupled to an eCSFS device 702. In someexamples, the eCSFS device 702 includes a hollow-pointed perforatedcannula 703, a platform 705 including a flow control mechanism (e.g., aone-way valve), and a drainage tube 707. The stent 700 is deployedwithin the sigmoid sinus 704 of a patient with the hollow-pointedcannula 703 inserted through the wall of the sigmoid sinus 704, throughthe arachnoid layer 706, and into the patient's subarachnoid space 708.In the deployed state, CSF in the subarachnoid space 708 passes throughthe perforations in the hollow-pointed cannula 703, through the flowregulation mechanism in the platform 705, and out of the drainage tube707 into the sigmoid sinus 704.

In general, the self-expanding coil type stent 700 is a coiled,spring-like member (e.g., a fine platinum or nitinol wire spring) which,when deployed, applies a constant outward radial force against thesigmoid sinus wall such that the stent 700 is anchored in place withinthe sigmoid sinus 704 by compressive force. Since the eCSFS device 702is coupled to the stent 700, the stent 700 acts to anchor the eCSFSdevice 702 in place.

Furthermore, the outward radial force applied by the stent 700 pressesthe eCSFS device 702 against the sigmoid sinus wall, thereby furtherstabilizing the position of the eCSFS device 702 in the sigmoid sinuswall.

In some examples, to deploy the stent 700, the stent 700 is firstcompressed (e.g., by twisting the coiled, spring-like member to reduceits diameter) and then loaded into a delivery catheter. The deliverycatheter is endovascularly guided to a desired location in the sigmoidsinus 704 or other sinus described herein. Once the delivery catheter,including the compressed stent 700 arrives at the desired location, thecompressed stent is released into the sigmoid sinus 704, causing thestent to decompress. Upon decompression of the stent 700, the diameterof the stent increases until the stent 700 conforms to the inner surfaceof the sigmoid sinus 704.

In some examples, the decompression of the stent 700 is not sufficientlyforceful to push the hollow-pointed cannula 703 through the wall of thesigmoid sinus 704 and through the arachnoid layer 706. In such examples,a force generating actuator (e.g., a balloon) is provided by thedelivery catheter and inserted into the coils 710 of the stent 700, suchthat when expanded, the hollow-pointed cannula 703 is forced through thewall of the sigmoid sinus 704, through the arachnoid layer 706, and intothe subarachnoid space 708.

2.1.2 Self-Expanding Circular Basket Type Stent

Referring to FIG. 8, another example of a stent 800 is implemented as aself-expanding circular basket, which is coupled to an eCSFS device 802.In some examples, the eCSFS device 802 includes a hollow-pointedperforated cannula 803, a platform 805 including a flow controlmechanism (e.g., a one-way valve), and a drainage tube 807. The stent800 is deployed within the sigmoid sinus 804 of a patient with thehollow-pointed cannula 803 inserted through the wall of the sigmoidsinus 804, through the arachnoid layer 806, and into the patient'ssubarachnoid space 808. In the deployed state, cerebrospinal fluid inthe subarachnoid space 808 passes through the perforations in thehollow-pointed cannula 803, through the flow regulation mechanism in theplatform 805, and out of the drainage tube 807 into the sigmoid sinus804.

In general, the stent 800 includes multiple collapsible tines 810 (e.g.,thin platinum or nitinol wires) interconnected by webs 812 in aconfiguration similar to the support ribs of an umbrella. In someexamples, the end of each tine 810 includes a barbed tip 814. Whenexpanded, the tines 810 of the stent 810 make contact with the innersurface of the sigmoid sinus wall and the barbs 814 collectively anchorthe stent 800 to the sigmoid sinus wall, thereby preventing the stent800 and the eCSFS device 802 from becoming dislodged.

In some examples, to deploy the stent 800, the tines 810 of the stent800 are first collapsed in a manner similar to closing an umbrella andthe collapsed stent 800 is loaded into a delivery catheter. The deliverycatheter is endovascularly guided to a desired location in the sigmoidsinus 804 or other sinus described herein. Once the delivery catheter,including the collapsed stent 800, arrives at the desired location, thecollapsed stent 800 is released into the sigmoid sinus 804, wherein thetines 810 of the stent 800 open in a manner similar to an umbrellaopening. Upon the opening of the tines 810, the barbed tips 814 of thetines 810 make contact with and latch into the inner surface of thesigmoid sinus 804, anchoring the stent 800 in place.

In some examples, the opening of the tines 810 of the stent 800 does notpush the hollow-pointed cannula 803 through the wall of the sigmoidsinus 804 and through the arachnoid layer 806. In such examples, a forcegenerating actuator (e.g., a balloon) is provided by the deliverycatheter and positioned adjacent to the hollow pointed cannula 803, suchthat when expanded, the hollow-pointed cannula 803 is forced through thewall of the sigmoid sinus 804, through the arachnoid layer 806, and intothe subarachnoid space 808.

2.1.3 Self-Expanding Circumferential Type Stent

Referring to FIG. 9, another example of a stent 900 is implemented as aself-expanding circumferential type stent, which is coupled to an eCSFSdevice 902. In some examples, the eCSFS device 902 includes ahollow-pointed perforated cannula 903, a platform 905 including a flowcontrol mechanism (e.g., a one-way valve), and a drainage tube 907. Thestent 900 is deployed within the sigmoid sinus 904 of a patient with thehollow-pointed cannula 903 inserted through the wall of the sigmoidsinus 904, through the arachnoid layer 906, and into the patient'ssubarachnoid space 908. In the deployed state, cerebrospinal fluid inthe subarachnoid space 908 passes through the perforations in thehollow-pointed cannula 903, through the flow regulation mechanism in theplatform 905, and out of the drainage tube 907 into the sigmoid sinus904.

In general, the stent 900 has the form of a mesh tube (e.g., a tubularmesh of fine platinum or nitinol wire) which, when expanded, conforms toan inner surface of the sigmoid sinus 904. The expanded stent 900applies a constant outward radial force against the sigmoid sinus wallsuch that the stent 900 is anchored in place within the sigmoid sinus904 by compressive force. Since the eCSFS device 902 is coupled to thestent 900, the stent 900 also acts to anchor the eCSFS device 902 inplace.

Furthermore, the outward radial force applied by the stent 900 pressesthe eCSFS device 902 against the sigmoid sinus wall, thereby furtherstabilizing the position of the eCSFS device 902 in the sigmoid sinuswall.

In some examples, to deploy the stent 900, the stent 900 is firstcompressed to reduce its diameter and fitted onto a force generatingactuator (e.g., a balloon) provided by the delivery catheter. Thedelivery catheter is endovascularly guided to a desired location in thesigmoid sinus 904 or other sinus described herein. Once the deliverycatheter with the compressed stent 900 fitted thereon reaches thedesired location, the balloon of the delivery catheter is caused toexpand, thereby expanding the stent 900 such that it conforms to theinner surface of the sigmoid sinus 904. The expansion of the balloonalso forces the hollow-pointed cannula 903 through the wall of thesigmoid sinus 904, through the arachnoid layer 906, and into thesubarachnoid space 908.

2.1.4 Self-Expanding Coil Type Stent

Referring to FIG. 10, another example of a stent 1000 is implemented asa self-expanding coil type stent which includes a number of individualcoils 1010 interconnected by one or more connecting members 1012 andcoupled to an eCSFS device 1002. In some examples, the eCSFS device 1002includes a hollow-pointed perforated cannula 1003, a platform 1005including a flow control mechanism (e.g., a one-way valve), and adrainage tube 1007. The stent 1000 is deployed within the sigmoid sinus1004 of a patient with the hollow-pointed cannula 1003 inserted throughthe wall of the sigmoid sinus 1004, through the arachnoid layer 1006,and into the patient's subarachnoid space 1008. In the deployed state,cerebrospinal fluid in the subarachnoid space 1008 passes through theperforations in the hollow-pointed cannula 1003, through the flowregulation mechanism in the platform 1005, and out of the drainage tube1007 into the sigmoid sinus 1004.

In some examples, the individual coils 1010 of the stent 1000 are fineplatinum or nitinol wire coils, which can expand to conform to an innersurface of the sigmoid sinus 1004. When deployed, the coils 1010 of thestent 1000 apply a constant outward radial force against the sigmoidsinus wall such that the stent 1000 is anchored in place within thesigmoid sinus 1004 by compressive force. Since the eCSFS device 1002 iscoupled to the stent 1000, the stent 1000 also acts to anchor the eCSFSdevice 1002 in place.

Furthermore, the outward radial force applied by the stent 1000 pressesthe eCSFS device 1002 against the sigmoid sinus wall, thereby furtherstabilizing the position of the eCSFS device 1002 in the sigmoid sinuswall.

In some examples, to deploy the stent 1000, the stent 1000 is firstcompressed, including compressing each of the coils 1010 of the stent1000 to reduce its diameter. The compressed stent 1000 is then loadedinto a delivery catheter. The delivery catheter is endovascularly guidedto a desired location in the sigmoid sinus 1004 or other sinus describedherein. Once the delivery catheter, including the compressed stent 1000arrives at the desired location, the compressed stent 1000 is releasedinto the sigmoid sinus 1004, allowing the stent 1000, including thecoils 1010 to decompress. Upon decompression of the stent 1000, thediameter of the coils 1010 increases until the coils 1010 conform to theinner surface of the sigmoid sinus 1004 at the delivery location.

In some examples, the decompression of the stent 1000 is notsufficiently forceful to push the hollow-pointed cannula 1003 throughthe wall of the sigmoid sinus 1004 and through the arachnoid layer 1006.In such examples, a force generating actuator (e.g., a balloon) isprovided by the delivery catheter and inserted into the coils 1010 ofthe stent 1000 such that when expanded, the hollow-pointed cannula 1003is forced through the wall of the sigmoid sinus 1004, through thearachnoid layer 1006, and into the subarachnoid space 1008.

2.1.5 Stent-Mounted Port

In some examples, one or more of the stents described above include aport structure attached to the stent. The port enables subsequentrepositioning or revision of the cannula and/or flow control mechanismof the eCSFS device. That is, a stent guided stable port is firstestablished between the sigmoid sinus (or other sinus described herein)and the intradural subarachnoid space. The port incorporates aself-sealing port to enable replacement of any cannula and/or flowcontrol mechanisms without leaving an open puncture site between thesigmoid sinus and the subarachnoid space. In some examples, the portsystem obviates the need for multiple repeated punctures, especiallywhen a cannula and/or flow control mechanism requires replacement.

Referring to FIG. 11, a self-expanding circumferential type stent 1100is deployed within the sigmoid sinus 1104 of a patient. A self-sealingport 1105 is mounted on the stent 1100 in such a way that the port 1105is held against an inner surface of the patient's sigmoid sinus 1104. Anexpanded view 1107 of the port 1105 shows that, in some examples, theport 1105 includes a self-sealing, penetrable, antithrombotic membrane1113 surrounded by a ring 1109.

In some examples, the membrane 1113 is penetrable due to a number ofslits 1111 which are cut through the membrane 1113. The slits 1111 arecut in such a way (e.g., a spiral cut resembling that of a camera leafshutter) that they sealingly close around any object inserted into theport 1105 and are sealingly closed when no object is inserted in theport 1105. In other examples, the membrane 1113 is a solid elasticmembrane (e.g., silastic or a silicone based alternative) which, uponpenetration by an object (e.g., an eCSFS device), forms a seal aroundthe object and, upon removal of the object, reseals itself. In someexamples, the membrane 1113 is fabricated using a material with inherentantithrombotic properties. In other examples, the membrane 1113 includesan antithrombotic coating.

In some examples, the ring 1109 is fabricated from material such asnitinol or platinum, possibly decorated with radiopaque material markersmade of gold or tantalum or another suitably radiopaque material. Insome examples, the ring 1109 includes, on its outer side, facing theinner surface of the patient's sigmoid sinus 1104, a groove with ahydrogel gasket (not shown) disposed therein. The outer side of the ring1109 including the hydrogel gasket makes contact with the inner surfaceof the patient's sigmoid sinus 1104. Upon contact with sigmoid sinusblood, the hydrogel gasket swells, providing a hermetic seal thatprevents sigmoid sinus blood from flowing around the port 1105 into theintracranial space.

Referring to FIG. 12, a self-expanding coil type stent 1200 including aself-sealing port 1205 is deployed within the sigmoid sinus 1204 of apatient. An eCSFS device 1213 (e.g., a corkscrew type eCSFS device) isinserted through the port 1205 with its tip 1215 in the patient'ssubarachnoid space and its drainage tube 1217 located in the patient'ssigmoid sinus 1204. Due to the above-described configuration of the port1205, the eCSFS device 1213 can be removed and replaced without havingto create another puncture site at a different location in the patient'ssigmoid sinus wall. Furthermore, the port 1205 ensures that fluid passesonly through the eCSFS device 1213 and does not leak into or out of thesubarachnoid space through the puncture site.

In some examples, the port is deployed in a patient's sigmoid sinus withan eCSFS device already installed within the port apparatus. In otherexamples, the port is deployed in the patient's sigmoid sinus without aneCSFS device installed through the port and the eCSFS device isinstalled through the port in a later step.

2.1.6 Alternative Stent Configurations

In some examples, the stent devices described above may include slots ormultiple miniature barbs which act to prevent migration of the stentwithin the smooth sinus endothelial layer of the sigmoid, transverse,straight, or sagittal sinus during and/or after deployment. In someexamples, the surface of the stent may be treated such that its outerwall is abrasive and prevents slippage within the smooth endotheliallayer during and/or after deployment.

In some examples, the stent devices described above are retrievable orrepositionable after deployment. In some examples, the stent devices areconstructed with an umbrella like mesh, providing the benefit ofcatching any foreign material that may be liberated or released bydeployment of the eCSFS device. In some examples, the umbrella like meshis retrievable through a specialized guide catheter.

In some examples, one or more of the stents described above includes adeployment mechanism including a controllable central sharp spicule thatis hollow such that it allows passage of cerebrospinal fluid. Thismechanism will enable the perforation of the sigmoid, transverse,straight, or sagittal sinus wall and while also allowing for the spiculeto be retracted into the device and removed if necessary. For example,the spicule, included in an eCSFS device is inserted through a stentmounted, self-sealing port structure (as described above) and is held inplace by friction in the self-sealing port structure. To remove thespicule, the eCSFS device including the spicule could be grabbed with anendovascular snare and pulled out of the self-sealing port structure andinto the venous system.

3 Alternative eCSFS Device Configurations

In the above description the eCSFS device is described as having acorkscrew type intracranial aspect. However, other examples of eCSFSdevices have been developed which allow safe placement of the device,stability of the device, penetration through the dura and arachnoid,apposition of the arachnoid to the dura after device deployment, andslight displacement of the brain parenchyma (e.g., the cerebellarcortex) so that it does not clog the device.

3.1.1 Corkscrew Type Self-Anchoring eCSFS Device

Referring to FIG. 13, a corkscrew type self-anchoring eCSFS device 1302(similar to the corkscrew shaped shunt described above) includes acorkscrew shaped perforated cannula 1303, a platform 1305 including aflow regulation mechanism (not shown), and a drainage tube 1307. In itsdeployed state, the corkscrew-shaped cannula 1303 is inserted through asigmoid sinus wall, through the arachnoid layer 1306, and into thesubarachnoid space 1308 of a patient. Cerebrospinal fluid flows throughthe perforations of the corkscrew shaped cannula 1303, through the flowcontrol mechanism in the platform 1305, and out of the drainage tube1307 with the flow control mechanism controlling the flow ofcerebrospinal fluid.

To deploy the corkscrew type self-anchoring eCSFS device 1302, the eCSFSdevice 1302 is first loaded into a delivery catheter. The deliverycatheter endovascularly guides the eCSFS device 1302 to a desireddeployment location in the sigmoid sinus 1304. Once at the desiredlocation, the tip of the corkscrew type self-anchoring eCSFS device 1302is pressed into a wall of the sigmoid sinus 1304 and the eCSFS device1302 is rotated such that the corkscrew shaped cannula 1303 passesthrough with wall of the sigmoid sinus 1304 with a screw-like motionuntil the platform 1305 rests against the wall of the sigmoid sinus 1304(or other sinus described herein). Once the eCSFS device 1302 is fullydeployed, the delivery catheter is withdrawn from the patient.

In addition to the features described in earlier sections, in someexamples, once deployed, the eCSFS device 1302 resists withdrawal fromsigmoid sinus wall due to the corkscrew shape of its cannula 1303.

3.1.2 Three-Dimensional Coil Type Self-Anchoring eCSFS Device

Referring to FIG. 14, a three-dimensional coil type self-anchoring eCSFSdevice 1402 includes a section of coiled three-dimensional-shapedperforated microcatheter tubing 1403 with a pre-definedthree-dimensional coil shape, a platform 1405 including a flowregulation mechanism (e.g., a one-way valve), and a drainage tube 1407.In its deployed state, the perforated tubing 1403 is disposed through asigmoid sinus wall and into the subarachnoid space 1408 of a patient,between the brain parenchyma 1409 and the arachnoid layer 1406.Cerebrospinal fluid flows through the perforations of the tubing 1403,through the flow control mechanism in the platform 1405, and out of thedrainage tube 1407 with the flow regulation mechanism controlling theflow of cerebrospinal fluid.

In general, the three-dimensional shape of the tubing 1403 pressesagainst the arachnoid layer 1406, causing the platform 1405 to be pulledtight against the wall of the sigmoid sinus 1404. This pulling of theplatform 1405 by the tubing 1403 pinches the sigmoid sinus wall and thearachnoid layer 1406 between the platform 1405 and the tubing 1403,anchoring the eCSFS device 1402 in place.

In some examples, the three-dimensional shape of the tubing 1403 pushesagainst the brain parenchyma 1409 to create a space for cerebrospinalfluid to pool around the tubing 1403. In general, at least some portionsof the tubing 1403, along with the perforations in the tubing, are notin contact with the brain parenchyma 1409. The portions of the tubing1403 not in contact with the brain parenchyma 1409 are less likely tobecome occluded and provide a consistently open, low resistancepassageway for cerebrospinal fluid to flow through the valve and out ofthe drainage tube 1407.

In some examples, to deploy the three dimensional coil typeself-anchoring eCSFS device 1402, the tubing 1403 of the device 1402 isfirst straightened out and loaded into a delivery catheter. The deliverycatheter is endovascularly guided to a desired location in the sigmoidsinus 1404 or other sinus described herein. Once the delivery catheterincluding the device 1402 reaches the desired location, the tubing 1403is pressed through the wall of the sigmoid sinus 1404, through thearachnoid layer 1406, and into the subarachnoid space 1408. In someexamples, the tubing 1403 is made from a material with shape memoryproperties such as nitinol (i.e., nickel titanium). In such examples, asthe tubing is fed into the subarachnoid space 1408 (or shortlythereafter), the tubing reverts to its original, predefinedthree-dimensional coil shape, pushing against the brain parenchyma 1409as is described above.

3.1.3 Umbrella Type Self-Anchoring eCSFS Device

Referring to FIG. 15, an umbrella type self-anchoring eCSFS device 1502includes an umbrella shaped screen 1511 covering a perforated hollowcannula 1503, a platform 1505 including a flow regulation mechanism(e.g., a one-way valve), and a drainage tube 1507. In its deployedstate, the perforated hollow cannula 1503 and the umbrella shaped screen1511 are disposed through a sigmoid sinus wall into the subarachnoidspace 1408 of a patient, between the brain parenchyma 1509 and thearachnoid layer 1506. Cerebrospinal fluid flows through the perforationsof the cannula 1503, through the flow regulation mechanism in theplatform 1505, and out of the drainage tube 1507 into the sigmoid sinus1504 with the flow regulation mechanism controlling the flow ofcerebrospinal fluid.

In general, the umbrella shaped screen 1511 presses against thearachnoid layer 1506, causing the platform 1505 to be pulled tightagainst the wall of the sigmoid sinus 1504. This pulling of the platform1505 by the umbrella shaped screen 1511 pinches the sigmoid sinus walland the arachnoid layer 1506 between the platform 1505 and the umbrellashaped screen 1511, anchoring the eCSFS device 1502 in place.

In some examples, the umbrella shaped screen 1511 pushes against thebrain parenchyma 1509 to create a space for cerebrospinal fluid to poolaround the perforated hollow cannula 1503. In general, the umbrellashaped screen 1511 prevents the brain parenchyma 1509 from makingcontact with and occluding the perforations in the perforated hollowcannula 1503, thereby maintaining a consistently open, low resistancepassageway for cerebrospinal fluid to flow through the valve and out ofthe drainage tube 1507.

In some examples, to deploy the umbrella type self-anchoring eCSFSdevice 1502, the umbrella shaped screen 1511 is collapsed in a mannersimilar to an umbrella being collapsed and the device 1502 is loadedinto a delivery catheter. The delivery catheter is endovascularly guidedto a desired location in the sigmoid sinus 1504 or other sinus describedherein. Once the delivery catheter including the device 1502 reaches thedesired location, the perforated hollow cannula 1503 and the collapsedumbrella shaped screen 1511 are pressed through the wall of the sigmoidsinus 1504, through the arachnoid layer 1506, and into the subarachnoidspace 1508. In some examples, the umbrella shaped screen 1511 is madefrom a material with shape memory properties such as nitinol (i.e.,nickel titanium). In such examples, once the umbrella shaped screen 1511is fully fed into the subarachnoid space 1508 (or shortly thereafter),the umbrella shaped screen 1511 opens to its original, predefinedumbrella shape, pushing against the brain parenchyma 1509 as describedabove. In other examples, once the umbrella shaped screen 1511 is fullyfed into the subarachnoid space 1504, the umbrella shaped screen 1511 ismechanically opened by an endovascular surgeon operating the deliverycatheter.

In some examples, the umbrella type self-anchoring eCSFS device 1502 canbe included as part of one or more of the stents described above.

3.1.4 Globe Type Self-Anchoring eCSFS Device

Referring to FIG. 16, a globe type self-anchoring eCSFS device 1602includes a multi-filament globe-like assembly 1611 surrounding aperforated hollow cannula 1603, a platform 1605 including a flowregulation mechanism (e.g., a one-way valve), and a drainage tube 1607.In its deployed state, the perforated hollow cannula 1603 and themulti-filament globe-like assembly 1611 are disposed through a sigmoidsinus wall into the subarachnoid space 1608 of a patient, between thebrain parenchyma 1609 and the arachnoid layer 1606. Cerebrospinal fluidflows through the perforations of the cannula 1603, through flowregulation mechanism in the platform 1605, and out of the drainage tube1607 into the sigmoid sinus 1605 with the flow regulation mechanismcontrolling the flow of cerebrospinal fluid.

In general, the multi-filament globe-like assembly 1611 presses againstthe arachnoid layer 1606, causing the platform 1605 to be pulled tightagainst the wall of the sigmoid sinus 1605. This pulling of the platform1605 by the multi-filament globe-like assembly 1611 pinches the sigmoidsinus wall and the arachnoid layer 1606 between the platform 1605 andthe multi-filament globe-like assembly 1611, anchoring the eCSFS device1602 in place.

In some examples, the multi-filament globe-like assembly 1611 pushesagainst the brain parenchyma 1609 to create a space for cerebrospinalfluid to pool around the perforated hollow cannula 1603. In general, themulti-filament globe-like assembly 1611 prevents the brain parenchyma1609 from making contact with and occluding the perforations in theperforated hollow cannula 1603, thereby maintaining a consistently open,low resistance passageway for cerebrospinal fluid to flow through thevalve and out of the drainage tube 1607.

In some examples, the multi-filament globe-like assembly 1611 can bemade in different sizes and different shapes with different radialstrengths.

To deploy the globe type self-anchoring eCSFS device 1602, the filamentsof the globe-like assembly 1611 are first compressed and the device 1602is loaded into a delivery catheter. The delivery catheter isendovascularly guided to a desired location in the sigmoid sinus orother sinus described herein. Once the delivery catheter including thedevice 1602 reaches the desired location, the compressed globe-likeassembly 1611 and the perforated hollow cannula 1603 are pressed throughthe wall of the sigmoid sinus, through the arachnoid layer, and into thesubarachnoid space. In some examples, the filaments of the globe-likeassembly 1611 are made from a material with shape memory properties suchas nitinol (i.e., nickel titanium). In such examples, once theglobe-like assembly 1611 is fully fed into the subarachnoid space (orshortly thereafter), the globe-like assembly 1611 is graduallyunsheathed, allowing the filaments of the globe-like assembly 1611 toreturn to their original, predefined globe-like shape, pushing againstthe brain parenchyma as described above.

Referring to FIG. 17, another example of a globe type self-anchoringeCSFS device 1702 includes a multi-filament globe-like assembly 1711surrounding a perforated hollow cannula 1703, a number of radial struts1705, a platform 1709 including a flow regulation mechanism (e.g., aone-way valve), and a drainage tube 1707. In its deployed state, theperforated hollow cannula 1703 and the multi-filament globe-likeassembly 1711 are disposed through a sigmoid sinus wall into thesubarachnoid space 1708 of a patient, between the brain parenchyma (notshown) and the arachnoid layer 1706. Cerebrospinal fluid flows throughthe perforations of the cannula 1703, through the flow regulationportion in the platform 1709 and out of the drainage tube 1707 into thesigmoid sinus 1704 with the flow regulation mechanism controlling theflow of cerebrospinal fluid.

In general, the multi-filament globe-like assembly 1711 presses againstthe arachnoid layer 1706, causing the platform 1709 and the radialstruts 1705 to be pulled tight against the wall of the sigmoid sinus1705. This pulling of the platform 1709 and the radial struts 1705 bythe multi-filament globe-like assembly 1711 pinches the sigmoid sinuswall and the arachnoid layer 1706 between the multi-filament globe-likeassembly 1711 and the platform 1079 and radial struts 1705, anchoringthe eCSFS device 1702 in place.

In some examples, to deploy the globe type self-anchoring eCSFS device1702, the filaments, including the radial struts 1705 of the globe-likeassembly 1711 are first compressed and the device 1702 is loaded into adelivery catheter. When compressed within the delivery catheter, theradial struts 1705 are in a straightened state where they extend alongan axial direction of the eCSFS device 1702 rather than along a radialdirection of the eCSFS device 1702. The delivery catheter isendovascularly guided to a desired location in the sigmoid sinus 1704 orother sinus described herein. Once the delivery catheter including thedevice 1702 reaches the desired location, the compressed globe-likeassembly 1711 and the perforated hollow cannula 1703 are pressed throughthe wall of the sigmoid sinus, through the arachnoid layer, and into thesubarachnoid space. In some examples, the filaments of the globe-likeassembly 1711, including the radial struts 1705 are made from a materialwith shape memory properties such as nitinol (i.e., nickel titanium). Insuch examples, once the globe-like assembly is fully fed into thesubarachnoid space (or shortly thereafter), the globe-like assembly 1711is gradually unsheathed. When unsheathed, the filaments of theglobe-like assembly 1711 are allowed to return to their original,predefined globe-like shape, pushing against the brain parenchyma asdescribed above. Similarly, when unsheathed, the radial struts 1705return to their original, predefined radially extending shape, pinchingthe sigmoid sinus wall between the radial struts 1705 and the globe-likeassembly.

In some examples, rather than automatically returning to its originalshape when unsheathed, the globe-like assembly 1711 is forced into itsoriginal, globe-like, shape by a surgeon (or another operator) pullingon a filament such as a wire which is attached to the top of the globe.In some examples, the eCSFS device 1702 includes a mesh or screen-likematerial which surrounds some or all of the globe-like assembly 1711,thereby preventing brain parenchyma from entering the globe-likeassembly 1711 where it could potentially occlude the perforations of thecannula 1703.

3.1.5 Alternative eCSFS Device Configurations

In some examples, one or more of the eCSFS devices described aboveincludes a self-sealing mechanism which prevents sinus blood (i.e., fromthe sigmoid, transverse, straight, or sagittal sinus) from flowingaround the platform of the device into the intracranial space. Forexample, the platform of the device may include a groove formed in itssurface facing the sigmoid sinus wall and a hydrogel gasket disposedwithin the groove. Upon contact with sigmoid sinus blood, the hydrogelgasket swells, providing a hermetic seal which prevents sigmoid sinusblood from flowing around the platform and into the intracranial space.

In some examples, the drainage tube of the eCSFS devices described abovemay extend along the internal jugular vein for a certain length,effectively mimicking a ventriculo-atrial shunt. In some examples,drainage tube of the eCSFS devices described above may be sufficientlydistant from the venous sinus wall to prevent its incorporation andsubsequent endothelialization in to the wall, which would result inocclusion of the eCSFS device.

In some examples the dimensions of the intracranial portions of theeCSFS devices described above are in the range of 3 mm to 1.5 cm. Insome examples, the portions of the eCSFS devices described above whichare located in the sigmoid sinus lumen have a dimension of approximately2 mm to 4 mm. In some examples, the length of the drainage tubes of theeCSFS devices described above is configurable such that it reaches thesuperior vena cava and right atrial junction. In some examples, theeCSFS devices described herein have a length in the range of 4 to 5centimeters.

In some examples, the eCSFS devices (and in particular, the drainagetube and the flow regulation mechanism) have a minimum diameter of 0.5mm to minimize occlusion of the device by plaque, protein clots, and/orblood clots.

In some examples, the eCSFS devices are safe for use in a magneticresonance imaging (MRI) machine.

In some examples, the eCSFS devices are removable and/or adjustableusing a loop or snare device.

In some examples, multiple eCSFS devices can be placed adjacently (i.e.,within 1 mm to 5 mm) in the sigmoid sinus.

In some examples, the platforms of the eCSFS devices described herein ismade of a material with shape memory properties such as nitinol (i.e.,nickel titanium).

In some examples, portions of the eCSFS device which are deployed in thelumen of the sigmoid sinus (e.g., the platform and the drainage tube)are coated in an anticoagulant material such as heparin to preventclotting of blood in, on, and around the portions of the eCSFS device.

In some examples, the eCSFS device includes a mechanism for detectingwhether cerebrospinal fluid is flowing through the device and wirelesslycommunicating that information to a technician. For example, theplatform or the cannula of the device may include a flow sensor whichsenses whether cerebrospinal fluid is flowing through the device and, insome examples, the flow rate of cerebrospinal fluid. Data collectedusing the flow sensor can be provided to wireless communicationcircuitry in the device which, upon request, wirelessly communicates theflow sensor data out of the patient's body to a communication deviceoperated by the technician. For example, the device may include RFIDcircuitry which is temporarily energized by radio frequency energyprovided from outside of the patient's body. Once energized, the RFIDcircuitry uses the flow sensor to collect data related to the flow ofcerebrospinal fluid through the device. The RFID circuitry thentransmits the collected data out of the patient's body using radiofrequency communications before it runs out of energy.

In some examples, the flow regulation valve in the platform of thedevice can be controlled (e.g., turned on, turned off, or adjusted) fromoutside of the patient's body (e.g., by using for example a magnet).

In some examples, the length of the drainage tube extending from theplatform into the venous system can be controlled as can be the diameterof the perforations in the hollow cannula in order to affect the rate offlow of cerebrospinal fluid into the shunt. In some examples, a pressuregradient across the eCSFS device can be regulated by the use of valveswith different pressure settings.

In some examples, the eCSFS devices described above are designed with anoptimal flow rate of approximately 10 cubic centimeters (cc) ofcerebrospinal fluid per hour (i.e., 200 cc-300 cc per 24 hour period).

In some examples, the eCSFS devices described above are designed toallow continuous flow of cerebrospinal fluid. In other examples, theeCSFS devices described above are designed for intermittent flow ofcerebrospinal fluid.

In general, all of the eCSFS devices described above include flowregulation mechanism such as a one-way valve.

Although the present disclosure has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. It ispreferred therefore, that the present disclosure be limited not by thespecific embodiments and implementations described herein, but only bythe appended claims.

4 Catheterization Apparatus

In some examples, delivery of an eCSFS device may require acatheterization apparatus that is specially designed for implantation ofthe eCSFS device in the sigmoid, transverse, straight, or sagittalsinus. For example, some patients such as those with a contralateralsinus stenosis or occlusion have a compromised alternative venouspathway. For these patients, full occlusion of the sigmoid sinus by, forexample, a balloon guide of a guide catheter might severely reduce orcompletely inhibit venous drainage of the cerebral tissue. Such areduction in venous drainage for an extended period of time such as thetime required to implant an eCSFS device is potentially dangerous forthe patient.

Referring to FIG. 18 a catheterization apparatus 1820 includes a guidecatheter 1822, a delivery catheter 1824, and two (or more) stabilizationballoons 1826 a, 1826 b. Very generally, the guide catheter 1822 is usedto endovascularly guide the catheterization apparatus 1820 to thesigmoid sinus 1804 (or other sinus described herein). While thecatheterization apparatus 1820 is being guided to the delivery location,the stabilization balloons 1826 a, 1826 b are deflated. Once thecatheterization apparatus 1820 arrives at the delivery location, thestabilization balloons 1826 a, 1826 b are inflated, stabilizing thecatheterization apparatus 1820 at the delivery location and causing anopening 1828 of the delivery catheter 1824 to be positioned against aninner surface of a patient's sigmoid sinus 1804.

Referring to FIG. 19, a cross-sectional view of the end of thecatheterization apparatus 1820 of FIG. 18 is shown. In thecross-sectional view, the catheterization apparatus 1820 is locatedwithin the sigmoid sinus 1804 with its stabilization balloons 1826 a,1826 b inflated and the opening 1828 of the delivery catheter 1824positioned against the inner surface of the patient's sigmoid sinus1804. Due to the use of two (or more) stabilization balloons 1826 a,1826 b, a significant portion 1830 of the lumen of the sigmoid sinus1804 remains unoccluded, allowing for the passage of blood through thesigmoid sinus 1804 during the eCSFS device implantation procedure.

Referring to FIG. 20, with the opening 1828 of the delivery catheter1824 positioned against the inner surface of the patient's sigmoid sinus1804, an eCSFS device 2002 is threaded through the delivery catheter1824, through the opening 1828 of the delivery catheter 1824, andpenetrates through the wall of the sigmoid sinus 1803 through thearachnoid layer 2006, and into the subarachnoid space 2008. Uponemerging from the delivery catheter 1824 through the opening 1828, thefilaments 2011 of the eCSFS device 2002 (a globe-type eCSFS device inthis case) are allowed to return to their original, predefinedglobe-like shape, pushing against the brain parenchyma. Similarly, uponemerging from the delivery catheter 1824, the radial struts 2005 returnto their original, predefined radially extending shape, pinching thesigmoid sinus wall between the radial struts 2005 and the globe-likeassembly.

Referring to FIG. 21, with the eCSFS device 2002 implanted, a surgeoncan confirm that the eCSFS device 2002 is working by aspiratingcerebrospinal fluid through a drainage tube 2134 that is within thedelivery catheter 1824 and attached to the eCSFS device 2002. Once theeCSFS device 2002 is confirmed as working, the stabilization balloons1826 a, 1826 b are deflated and the drainage tube 2134 is detached(e.g., by electrolytic detachment) at a detachment point 2132.

Referring to FIG. 22, with the eCSFS device 2002 implanted andfunctioning in the sigmoid sinus 1804, the catheterization apparatus1820 is withdrawn, completing the eCSFS implantation procedure.

Referring to FIG. 23, in some examples, it is necessary to test thepatency (i.e., the openness) of a previously implanted eCSFS device2302. In one example, to do so, a catheterization apparatus 2320 has afemale receptacle 2334 mounted on one or more of the stabilizationballoons 2326 and attached to a drainage catheter 2336 of thecatheterization apparatus 2320. The catheterization apparatus 2320 isnavigated to the site of the eCSFS device 2302 and the female receptacle2334 is sealingly placed over the drainage tube 2307 of the eCSFS device2302. A surgeon then attempts to draw cerebrospinal fluid through theeCSFS device and into the drainage catheter 2336. If cerebrospinal fluidis successfully drawn through the eCSFS device 2302, then the eCSFSdevice 2302 is open. Otherwise, the eCSFS device 2302 is occluded.

In some examples, the eCSFS device includes a radiopaque material thataids in guiding the catheterization apparatus 2320 to the deliverylocation and placing the female receptacle 2334 over the drainage tube2307 of the eCSFS device 2302.

In some examples, the catheterization apparatus includes a steerablecomponent in order to maintain the working port of the guide catheter indirection parallel to with the intracranial surface of the sigmoidsinus. In some examples, in order to evaluate a proximity of the eCSFSdevice to the sigmoid sinus wall and to evaluate the dural and arachnoidlayers separating the device from the cerebrospinal fluid, thecatheterization apparatus includes a phased array ultrasound microcatheter. In other examples, in order to evaluate a proximity of theeCSFS device to the sigmoid sinus wall and to evaluate the dural andarachnoid layers separating the device from the cerebrospinal fluid, thecatheterization apparatus includes an OCT (optical coherence tomography)micro catheter imaging device.

In some examples, the opening at the end of the delivery catheter of thecatheterization apparatus is specially configured to dock with the stentmounted ports described above. In some examples, rather than usingstabilization balloons, the catheterization apparatus may include atemporary stent for stabilizing the delivery catheter and positioningthe opening of the delivery catheter against the wall of the sigmoidsinus.

In some examples, rather than including two separate stabilizationballoons, the catheterization apparatus includes a single stabilizationballoon with an asymmetric shape such that the delivery catheter caneasily be pushed against a wall of the sigmoid sinus in an area over thepuncture site.

5. General Considerations for eCSFS and Deployment Devices

Exemplary dimensions for endovascular CSF shunt (eCSFS) deviceembodiments of the present disclosure are described herein. eCSFSdevices should be dimensioned and configured to eliminate or minimizeany disruption to sinus blood flow and occlusion within the sinus lumen.The aforementioned eCSFS deployment sites have been selected with thisconsideration in mind. That is, the dural venous sinuses described inthis application (i.e., sigmoid, transverse, straight, or sagittalsinus) can have a relatively large diameter (e.g., 7 mm, 8 mm, 9 mm ormore) compared to other dural venous sinuses. The increased sinusdiameter accommodates eCSFS devices as described herein, whileminimizing the impact of deployment procedures and a deployed device onvenous blood flow within the sinus. A specialized catheterizationapparatus has also been disclosed, which minimizes sinus occlusionduring eCSFS deployment to preserve venous drainage of cerebral tissue.

The subarachnoid portions of the eCSFS device embodiments disclosedherein can include a shielding mechanism that protects the surface ofthe eCSFS, and in particular any openings in the surface of the eCSFSdevice that are designed to enable the passage or flow of CSFtherethrough, from surrounding brain parenchyma (e.g., cerebellum) witha stent-like, umbrella-type, or equivalent configuration. The shieldingmechanisms enable continuous CSF flow through the eCSFS device andmitigate clogging by structurally separating brain parenchyma tissuefrom the portions of the shunt device that are implanted into thesubarachnoid space. These shielding mechanisms are particularlyimportant if an eCSFS device is not deployed in a well-establishedsubarachnoid cistern or where there is little or no CSF-filled spacebetween the arachnoid layer and the pia. For example, in patientsyounger than 80 years old, the subarachnoid space accessible from thesigmoid sinus can include little or no CSF-filled space (e.g., 0-1 mmbetween arachnoid and pia) to accommodate the subarachnoid portion of aneCSFS device. The shielding aspects of the eCSFS devices address thischallenge by advantageously creating, augmenting, and/or maintaining asubarachnoid cistern for eCSFS devices in such patients.

OTHER EMBODIMENTS

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made without departing fromthe spirit and scope of the disclosure. Accordingly, other embodimentsare within the scope of the following claims.

The invention claimed is:
 1. A method for draining cerebrospinal fluidfrom a patient's subarachnoid space into the venous system, the methodcomprising: providing a shunt having opposed first and second ends,wherein the first and second ends are in fluid communication to enablethe cerebrospinal fluid to be drained from the subarachnoid spacethrough the first end and second end into the venous system;endovascularly delivering the shunt to a dural venous sinus; stabilizingthe shunt against an inner wall of the dural venous sinus at a desiredlocation proximal to the subarachnoid space; implanting a portion of theshunt through the venous sinus wall of the patient; and drainingcerebrospinal fluid from the patient's subarachnoid space into thepatient's venous system.
 2. The method of claim 1, further comprising:placing the shunt percutaneously into the venous system of the patientwithout the need for open surgery.
 3. The method of claim 1, furthercomprising draining the cerebrospinal fluid into a venous sinus lumen ofthe patient.
 4. The method of claim 1 further comprising providing theshunt with a radiopaque material.
 5. The method of claim 1 furthercomprising stabilizing the shunt with a collapsible member.
 6. Themethod of claim 1 wherein a stabilizing member applies a constantoutward radial force and anchors the shunt against the inner wall of thedural venous sinus at the desired location proximal to the subarachnoidspace.
 7. The method of claim 1 wherein the dural venous sinus isaccessed via a femoral vein or jugular vein.
 8. The method of claim 1wherein the dural venous sinus comprises a sigmoid sinus.
 9. Anendovascularly implantable shunt device for draining cerebrospinal fluidfrom a patient's subarachnoid space into the venous system, the devicecomprising: a shunt having opposed first and second ends; a hollowpassageway extending between the first end and the second end such thatcerebrospinal fluid can be drained through the second end into thevenous system; a stabilizing mechanism coupled to the shunt andconfigured to anchor the shunt against an inner wall of a dural venoussinus and at a desired location proximal to the subarachnoid space. 10.The implantable shunt device of claim 9, wherein the stabilizingmechanism comprises a stent device configured for insertion into thesinus of the patient.
 11. The implantable shunt device of claim 10,wherein the stent device includes a self-sealing port configured to havethe shunt disposed therethrough.
 12. The implantable shunt device ofclaim 11, wherein the port includes a radiopaque ring.
 13. Theimplantable shunt device of claim 9, wherein at least one part of theshunt device includes a radiopaque material.
 14. The implantable shuntdevice of claim 9, wherein the second end of the shunt is constructed topenetrate a wall of a dural venous sinus of the patient.
 15. Theimplantable shunt device of claim 9, wherein the shunt device comprisesa shielding mechanism coupled to the shunt and sized and configured toshield a portion of the shunt implanted in the subarachnoid space fromsurrounding brain parenchyma tissue.
 16. The implantable shunt device ofclaim 15, wherein the shielding mechanism comprises an umbrella-shapedmember or a globe-shaped member.
 17. The implantable shunt device ofclaim 16, wherein the umbrella-shaped member or globe-shaped memberincludes a screen covering.